The present invention generally relates to context free grammars. More specifically, the present invention relates to an authoring system for use in authoring such grammars.
Semantic-based robust understanding technology has been widely used in human/machine conversational systems. In fact, it has been shown to be one of the most competitive technologies after many years of work in the area of spoken language understanding. However, this technology suffers from a number of disadvantages. One of the main disadvantages is the requirement for expertise in manual development of a domain-specific grammar. It is believed that this is a major obstacle faced by many developers in building a conversational system.
Researchers have attempted to remedy this problem. For instance, some researchers have been working in an attempt to develop data-driven automatic grammar inference for many years. However, the success of this type of system has been very limited due to the fundamental problem of sparse data for the complex target grammar.
A semantic context free grammar (CFG), like a syntactic CFG, defines the legal combination of individual words into constituents, and the combination of constituents into sentences. In addition, a semantic CFG must define the concepts and relationships among those concepts in a specific domain. It is this additional dimension of variation that makes it necessary to develop a grammar for every new domain.
It is also common for semantic information in such applications to be defined in a semantic schema. Semantic schema is often used for many different purposes. For example, semantic schema serves as the specification for a language-enabled application. In other words, once a semantic schema is defined, grammar and application logic development can proceed simultaneously according to the semantic schema. Semantic schema also plays a critical role in dialog management. Further, the semantic schema is language independent, in the sense that it does not specify the linguistic expressions used to express a concept. Therefore, it is used not only for language-enabling applications, but also for integrating inputs from multi-modalities, such as mouse click events. Thus, in many such applications, the semantic schema must be authored and already exists prior to the development of the CFG.